Zimmermann cleared waivers Saturday and was sent outright to Triple-A Norfolk, Jake Rill of MLB.com reports.
Zimmermann hasn't pitched in the majors this season, and he was designated for assignment Thursday to clear space on the 40-man roster for infielder Emmanuel Rivera. After clearing waivers, Zimmermann will stick around in the organization continue to serve as rotational depth at Norfolk, with whom he has produced a 4.64 ERA and 1.47 WHIP through 66 innings this season.